buildkite: update Go

#6322 tried to update Go to 1.16, but existing nodes fail to upgrade due to the
presence of old Go [1]. Specifically when trying to add Go to `/usr/bin`:

```
ln: failed to create symbolic link '/usr/bin/go': File exists
```

Also:
- Removing `golang-go` also removes apt installs of `gcc` and `pkg-config`, so
  those are installed explicitly.
- Add `-c` to wget, which will prevent re-downloading Go for each run.
- Disable GO111MODULE when building cri-tools and containerd, since we're using
  pre-module versions of each.

1 - https://buildkite.com/gvisor/pipeline/builds/7285#3593244c-e411-472d-804a-9c7fbbd24762

PiperOrigin-RevId: 386106881

.buildkite/hooks/pre-command

@@ -8,9 +8,17 @@ function install_pkgs() {
   done
 }
 install_pkgs make "linux-headers-$(uname -r)" linux-libc-dev \
-  graphviz jq curl binutils gnupg gnupg-agent golang-go \
+  graphviz jq curl binutils gnupg gnupg-agent gcc pkg-config \
   apt-transport-https ca-certificates software-properties-common
 
+# Install Go 1.16, as only 1.13 is available via apt. If it's installed via apt,
+# remove it.
+sudo apt-get autoremove -y golang-go
+declare -r go_archive=go1.16.6.linux-amd64.tar.gz
+wget -c "https://golang.org/dl/${go_archive}"
+sudo tar -xzf "${go_archive}" -C /usr/local
+sudo ln -s /usr/local/go/bin/go /usr/bin/go
+
 # Setup for parallelization with PARTITION and TOTAL_PARTITIONS.
 export PARTITION=${BUILDKITE_PARALLEL_JOB:-0}
 PARTITION=$((${PARTITION}+1)) # 1-indexed, but PARALLEL_JOB is 0-indexed.

tools/installers/containerd.sh

@@ -20,6 +20,9 @@ declare -r CONTAINERD_VERSION=${1:-1.3.0}
 declare -r CONTAINERD_MAJOR="$(echo ${CONTAINERD_VERSION} | awk -F '.' '{ print $1; }')"
 declare -r CONTAINERD_MINOR="$(echo ${CONTAINERD_VERSION} | awk -F '.' '{ print $2; }')"
 
+# We're running Go 1.16, but using pre-module containerd and cri-tools.
+export GO111MODULE=off
+
 # Default to an older version for crictl for containerd <= 1.2.
 if [[ "${CONTAINERD_MAJOR}" -eq 1 ]] && [[ "${CONTAINERD_MINOR}" -le 2 ]]; then
   declare -r CRITOOLS_VERSION=${CRITOOLS_VERSION:-1.13.0}
@@ -29,8 +32,8 @@ fi
 
 # Helper for Go packages below.
 install_helper() {
-  PACKAGE="${1}"
-  TAG="${2}"
+  declare -r PACKAGE="${1}"
+  declare -r TAG="${2}"
 
   # Clone the repository.
   mkdir -p "${GOPATH}"/src/$(dirname "${PACKAGE}") && \
@@ -71,8 +74,8 @@ done
 
 # Install containerd & cri-tools.
 declare -rx GOPATH=$(mktemp -d --tmpdir gopathXXXXX)
-install_helper github.com/containerd/containerd "v${CONTAINERD_VERSION}" "${GOPATH}"
-install_helper github.com/kubernetes-sigs/cri-tools "v${CRITOOLS_VERSION}" "${GOPATH}"
+install_helper github.com/containerd/containerd "v${CONTAINERD_VERSION}"
+install_helper github.com/kubernetes-sigs/cri-tools "v${CRITOOLS_VERSION}"
 
 # Configure containerd-shim.
 declare -r shim_config_path=/etc/containerd/runsc/config.toml